I. Field of the Invention
This invention relates to disposable liners or sacs for use in a nurser bottle. More particularly, the invention relates to preformed, pre-sterilized and disposable liners that can be stacked and nested within a packaging container.
With the expanded use of disposable liners, a need has developed for a liner constructed so that a plurality of liners can be conveniently stored in a minimum amount of space, while maximizing thus also the size or capacity of each individual liner. A common problem is the size of the container and the shelf space that can be allocated to hold a sufficient number of liners. To minimize the amount of space, the liners need to be in a nesting arrangement, e.g., one upon another, within a container. However, this nesting arrangement must not diminish the total capacity of each liner to a level that is substantially below the capacity of existing liners. For example, since a vast majority of liners are of a capacity to hold eight ounces of fluid, it is desirable to design a liner that meets this industry requirement.
With such a nesting arrangement, there is an additional need for each liner to readily disengage from the remainder of the stack during dispensing. Thus, there has been, heretofore, a need for an inexpensive, disposable liner in which a large number of liners can be stacked in a defined area and, yet, each liner can be readily separated from the remainder of the stack while meeting industry capacity requirements.
II. Description of the Prior Art
Nurser liners that have an upper, firm flange or rim to facilitate the positioning and assembly of the liner on a holder are shown in U.S. Pat. No. 958,328 to Decker, which issued on Feb. 28, 1911; U.S. Pat. No. 2,110,928 to De Buys, which issued on Mar. 15, 1938; U.S. Pat. No. 2,508,481 to Allen, which issued on May 23, 1950; and U.S. Pat. No. 3,776,408 to Wald, which issued on Dec. 4, 1973.
Also, nurser liners that permit an individual liner to separate freely from the remaining liners are known. For example, U.S. Pat. No. 3,851,781 to L. S. Marco, which issued on Dec. 3, 1974, provides a disposable plastic container having an upper wall portions or step and a lower wall portion or step that are configured to permit stacking of the containers in package form. For stacking two containers, the lower wall portion of one container rests on top of the upper wall portion of the other container. Thus, individual containers can be readily removed from the nested stack as long as each container has two wall portions or steps. Also, U.S. Pat. No. 3,970,206 to P. G. Morash, which issued on Jul. 20, 1976, provides a similar construction of stackable feeding assemblies.
However, the above patents do not provide a nurser liner having a unique structural design for nesting and for stacking a plurality of such liners within a limited amount of space while maximizing each liner's capacity. Furthermore, these liners also do not minimize the material costs and the amount of space needed in a container.